Mounting for vacuum tubes



Jain. 20v 925- LSZEf/lf@ W. A. KNOOP MOUNTNG FOR VACUUM TUBES Filed Nov. 30, 1923 Patented dan.. 20, 1925..'

min/1A. "xNoor, COMPANY, INCORPORATED, or Nnw YORK, N. Ywn conronATIoN or Nnw Yoan.l

mais@ rasant naaien.

OF BROOKLYN, NEW YORK, ASSIGNOR'TO WESTERN ELECTRIC Y MOUNTING FOR VACUUM TUBES.

`Application filed November 301923. Serial No. 677,825.

To all who/mit may concern.'

Beit known that I, WILLIAM A. KNoor, a

' citizen of the United States of America,

residing at Brooklyn, in the county of Kings, -State of New York, have invented certain newA and useful lImprovements in 'Mountings for Vacuum Tubes, of which the 'following is a full, clear, concise, and 'exact description.

This invention relates lto a mounting for vacuum tubes, and has for an wobject the reduction of noise in a vacuum tube circuit caused by external disturbances.A

It 1S common practice to use vacuum signal currents which have been transmitted over long lines. These currents are often .s0 weak' that very small variations in the space current of the vacuum tube amplifier' will produce fluctuations in the output current comparable with the fluctuations producedv by the signals themselves. This is especially true at the receiving end of long submarine cable circuits where the input currents in the first stage of amplifica-tion are exceedingly small.

Any variation in the space relation of the electrodes of a vacuum tube will produce variations in the space current, so that when such a tube is used to amplify Weak signals, the effects due to the va-riation of the space relation ofthe electrodes may produce output currents of the same order of magnitude as the amplified signals. This variation in the space relation of the electrodes may be caused by mechanical vibrations ofthe tube produced by some external source. These vibrations may/.be transmitted to the tube either through its sup- .port or `through the air. In the latter case, of course, the vibrations cannot be tra-nsmitted directly to the electrodes, as they .are inclosed in an evacuated tube, but must reach them through the socket. Some of the energy of these vibrations may be absorbed by a resilient support for the tube but it has beenfound that this is not sufricient to absorb all the energy of the vibrations.

External vibrations impressed on the vacuum tube appreciably disturb the space relation of the electrodes,-on1y when they tubes for amplifying or repeating weaky cies much lower than could possibly produce vibration of the electrodes, cause a detrimental variation in the space current of the tube. This is due to the slow swaying of the tube in the surrounding electrical field which produces variations in the electrostatic field between the electrodes, thus causing harmful disturbances in the space current. Since these disturbances are of a low frequency, they are particularly objectionable in telegraph signaling.

This invention, in one form, comprises means for resiliently supporting a Vvacuum tube together with means for properly damping any vibration which. might be produced in the tube and for protecting the tube against external electrical fields. The embodiment of the invention described herein comprises an elastically supported vacuum tube socket having projections immersed in a damping fluid.

Referring to the drawings, Fig. 1 shows a side elevation and Fig. 2, a front elevation of one form of this invention; Fig. 3 illustrates a telegraph circuit in which this invention may be used; and Fig. 4 shows a jplan view and Fig. 5, a front elevation' of another form of this invention.

Referring to Figs. l and 2, a vacuum tube 4, which may be of the three-electrode type, is shown mountedin a horizontal position in a socket 5. The socket is of the usual type provided with fourA contacts 6 for connecting the tube to the circuit in which it is to be used. A vertical panel 7 is shown to which the socket 5 is attached by mea-ns of four rubber bands 9. These bands are fastened to the socket by means of four screwhooks 10 and to the panel by four screws 8. A metal screen 1l fastened to the panel is provided for protecting the tube against mechanical injury.

The bands 9 are not always effective in I quency vibrations `which would otherwise lil) produce swaying of the tube is absorbed. As explained above, this swaying of the entire tube produces harmful disturbances due to the effect on the space current of the movement of the tube through the external electrical ield.

It was found that slight movements of the vanes caused large changes in the distribution of the electrical charges which accumulated on them. This electrostatic disturbance was also eii'ective in producing variations in the space current of the tube.

' Means is therefore provided for preventing the accumulation of electrical charges on the vanes and oil pot. As shown, this means comprises flexible wire 17 connecting the vanes to the pot 16 which is in turn connected to ground, as shown by the connection 18. o v

Referring to Figs. 4 and 5, panel 27 is shown to which is attached by two screws 29 an oil pot 28. Integral with the pot are two supporting members -26 to which are attached two helical springs 37. VFrom these springs is suspended by means of four Z-` shaped brackets 30 a vacuum tube socket 25, these brackets being attached to the base of the socket, as shown. A vacuum tube 24 which may be of the three-electrode type is supported in an upright position in the socket. Contact terminals 31 are provided for connecting the tube to the circuit with which it is associated. Attached to the socket base are two arms 32 to which are joined mutually perpendicular vanes 33, 34 and 35 which are immersed in the body of oil in such position that during normal operation they will not come into contact with the walls of the oil pot. These vanes are conected to the oil pot by means of a flexible wire 38. The pot is in turn connected to ground through a wire 39.

Fig. 3 shows a system in which it was found desirable to use this typeof mounting. Three tandem connected vacuum tubes 19, 20 and 21 are shown in a submarine cable amplifier circuit. The submarine cable 22 is connected to the input circuit of the first tube 19 through a transformer 23, the connections being arranged in the usual manner to provide two-way operation. The output Acircuit of the last tube 21 is connected to a telegraph recording instrument 26.. Telegraph signals coming `mounting herein described. This is usually sufficient to eliminate disturbances due to vibration of the tubes as the input current in the succeeding stages is greater than any current that could be produced by mechanical vibrations of the tube. In some 1nstallations, however, it might be found necessary to provide the mounting for one or more of the succeeding stages.

It is to be understood that this invention is not limited to the particular arrangements above described, but that the structure may be variously modiiied, without departing from the spirit of the invention as' defined bythe appended claims.

What is claimed is: 1. In combination, a vacuum tube havin electrodes `in fixed space relation to eac other, a resilient support for said tube, and means for damping vibrations of the tube, said means comprising a body attached to the tube and immersed in a body of damping fiuid.

. 2. A support for a vacuum tube comprising a base, resilient means 4for supporting said tube on said base, a pot containing a damping Huid. a body attached to the tube and immersed in 4said fluid, and means for grounding said body and said pot.

3. A support for a' vacuum tube comprising a socket for said tube, a base, resilient means for attaching said socket to said base, a pot containing oil, three mutually perpendicular vanes attached to saidy socket and immersed in -saidoil, and means for connecting to ground said vanes and said pot.

4. The combination of a vacuum tube having a cathode. an anode and a controlv electrode in fixed space relation to each other, means for preventing variation in the space relation of` the electrodes due to vibrations transmitted from external sources and for preventing any motion of the tube with respect to the surrounding electric lield, said means comprising a resilient support for said tube and a stationary oil bath in which a plurality of vanes attached to said tube are immersed. j

5. A support for a vacuum tube comprising a socket for'said tube, `a plurali of springs for supportin said socket, a ath of damping fluid, a p urality of vanes at- 1,5as,4so

uclliled to said socket vand immersed in said 6. A support for a vacuum tubo comprisin a, socket for said tube, a plurality of 5 he ical springs for suspending said socket,

a pot containing damplng Huid, a plurality of vanes attached to said socket and immy name this 27th day of November A. D., 1923.

LL A., KNUUP, 

